import java.util.Arrays;

public class L344R {
    public static void main(String[] args) {
        String str = "hello";
        new Solution().reverseString(str.toCharArray());
    }

    static class Solution {
        public void reverseString(char[] s) {
            int left = 0;
            int right = s.length - 1;
            while (left < right) {
                char tmp = s[left];
                s[left] = s[right];
                s[right] = tmp;
                left++;
                right--;
            }

        }
    }
}
